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Radiated Electromagnetic Field Test
Effectiveness of MG Vest in Preventing ICD Malfunctions Due to Impulse Noise
| Objective | Method | Results | Discussion | Conclusion | References |
Objective
This experiment evaluated the MG Vest’s ability to prevent unnecessary defibrillation shocks by ICDs through an impulse noise test that irradiates a wide frequency band from 0 Hz to 1 GHz.
Method
An anthropomorphic phantom was equipped with an ICD, and a radiation probe (MODEL: 01-00009A, φ150mm) manufactured by Noise Laboratory Co., Ltd. was positioned above it at the location most prone to malfunction (Figure 1). A noise simulator (INS-400AX, also by Noise Laboratory Co., Ltd.) was used to inject repetitive square waves into the probe, and unnecessary defibrillation shocks were monitored. The pulse had an amplitude of 4 kV, a pulse width of 1 μs, and a rise time of <1 ns, repeated every 16 ms, with a total irradiation time of 3 minutes.
Three ICD models were tested.
Results
Among the three ICD models tested, one model exhibited an unnecessary defibrillation shock during the impulse noise test. When the MG Vest was worn, this unnecessary shock did not occur.
| ICD | VF Detection Count (No MG Vest) | VF Detection Count (With MG Vest) |
|---|---|---|
| A | 0 | N/A |
| B | 0 | N/A |
| C | 1 | 0 |
(N/A: Data not available)
Discussion
Although strong electromagnetic noise like that used in the impulse noise test is unlikely to occur in everyday life, studies by Japan’s Ministry of Internal Affairs and Communications have reported that electromagnetic waves emitted from anti-theft devices¹ and stationary RFID readers² can cause unnecessary ICD shocks. Therefore, the risk of such events in daily life cannot be dismissed.
Conclusion
It was confirmed that the MG Vest is effective in preventing unnecessary ICD defibrillation shocks caused by electromagnetic waves.
The findings of this study were presented on November 19, 2005, at the 5th ICD (Implantable Cardioverter Defibrillator) Public Research Symposium. [Presentation Details]
References
- 1) Results of the Ministry of Internal Affairs and Communications' survey on electromagnetic wave effects on medical devices (examining effects of electronic article surveillance systems and wireless LANs on implanted medical devices), June 18, 2004
- 2) Results of the Ministry's follow-up survey on new mobile phone models and RFID equipment impacts on implanted medical devices, August 11, 2005